Vehicle Control System, Vehicle Control Method, and Vehicle Control Program

ABSTRACT

A vehicle control system includes a route setting unit for setting a route from a start point to a destination; an information obtaining unit for obtaining from a memory position information of at least one base point and at least one control point existing in the route set by the setting unit; a base point recognition unit for recognizing that a current position of a vehicle reaches a position of the base point obtained by the obtaining unit; a running situation monitoring unit for determining as a predetermined distance a running distance from the base point most lately recognized by the recognition unit; and a control unit for executing an advanced control to the vehicle if the predetermined distance obtained by the monitoring unit is shorter than any of first and second threshold distances, when the current position reaches a position of the control point obtained by the obtaining unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle control system, a vehiclecontrol method, and a vehicle control program.

2. Description of the Related Art

Conventionally, a vehicle control system is studied that automaticallydetermines the control item of a running vehicle, based on a vehiclecurrent position. For example, a system disclosed in Japanese PatentLaid-Open Publication No. 2005-132291 determines a current position of avehicle according to a radio wave navigation based on the receivedinformation of a GPS (Global Positioning System) radio wave and a hybridnavigation based on an autonomous navigation based on informationacquired by the vehicle without using the GPS radio wave. Then dependingon the likelihood (degree of certainty) of the current position, thesystem changes the control item of the vehicle.

However, according to the method of using the GPS radio wave, thereoften occur cases that a driver himself/herself manually drives his/hervehicle, canceling the control of the vehicle when the receptionenvironment of the GPS radio wave becomes worse. Thus the driver isforced to manually drive the vehicle every time when the vehicle controlis cancelled, and therefore the usability of the vehicle control is bad.

In addition, in such a case of passing through a high-rise buildingblock, the influence of the GPS accuracy worsening appears due to aradio wave around the vehicle. As a result thereof, such a number of GPSreceiving satellites is reduced, and the certainty of a vehicle currentposition is worsened.

Accordingly, with respect to the accuracy worsening due to the receptionenvironment of the GPS radio wave, because it is not forecasted when theaccuracy is worsened, the continuity of the vehicle control cannot bekept and there is no way other than canceling the vehicle control.Although a method of simulating an operation situation of a GPSsatellite in advance can also be thought, in practical it is notrealistic, considering the influence of multi-paths due to thereflection and the ever-changing of a real environment in such a realbuilding block.

On the other hand, the method of determining a vehicle current positiononly by an autonomous navigation without using the GPS radio wave. Theautonomous navigation has an advantage of being difficult to beinfluenced by the receiving environment of the GPS radio wave. However,because the autonomous navigation is the method of accumulating amovement distance calculated from a speed and a direction measured by adriver's own vehicle, an error between a vehicle current positioncalculated by the autonomous navigation and an original vehicle currentposition is accumulated as the movement distance becomes longer.

It is not desirable to execute a sophisticated vehicle control when theerror is large (in other words, the degree of certainty is bad).Accordingly, when the error is large, a vehicle control should be takenthat is not sophisticated such a deceleration. Furthermore, the accuracyof a vehicle current position whose target is a vehicle control isneeded to be higher than that of a vehicle current position whose targetis the map matching of a car-navi (car navigation).

In the conventional determination method of a driver's own vehiclecurrent position whose target is the map matching, a map display is aprecondition; therefore, the vehicle current position is determined,then the processing of the map matching is executed, and the vehiclecurrent position on the map is determined. In the processing of the mapmatching, because an association between a road on an erroneous map anda running position using the map, there is a possibility that the mapmatching is forcibly matched with a nearest road. This is because ajudgment is conventionally taken that the slight difference of a displayposition does not become a critical problem since the map display ismade the precondition.

Consequently, there is a need for providing a driver with a convenienceby broadening the control range of a vehicle control, based on thecalculation error of a vehicle current position.

SUMMARY OF THE INVENTION

A vehicle control system of the present invention comprises: a routesetting unit configured to set a route from a start point to adestination; an information obtaining unit configured to obtain from amemory means base points and control points of position informationexisting in the route set by the route setting unit; a base pointrecognition unit configured to recognize that a vehicle current positionof a running vehicle reaches each position of the base points obtainedby the information obtaining unit; a running situation monitoring unitconfigured to determine as a predetermined distance a running distancefrom a newest one of the base points recognized by the base pointrecognition unit; and a control unit configured to execute an advancedcontrol to the running vehicle if the predetermined distance determinedby the running situation monitoring unit is shorter, when the currentposition of the running vehicle reaches each position of the controlpoints obtained by the information obtaining unit. Other means will bedescribed later.

In accordance with the present invention a control degree of a vehicleis determined, based on a predetermined distance according to acalculation error of a vehicle current position. Accordingly, bybroadening a control range of a vehicle control, it is possible toprovide a driver with a convenience.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration drawing showing an outline of a vehiclecontrol relating to an embodiment of the present invention.

FIGS. 2A and 2B are illustration drawings showing a correlation betweena running distance and a cumulative error relating to the embodiment.

FIG. 3 is a state change drawing showing that a control item is changedaccording to a running distance from a base point relating to theembodiment.

FIG. 4 is a configuration drawing showing a vehicle control systemmounted on a vehicle relating to the embodiment.

FIG. 5 is a flowchart showing an operation outline of the vehiclecontrol system relating to the embodiment.

FIGS. 6A and 6B are illustration drawings showing a structure of basepoint data relating to the embodiment.

FIGS. 7A and 7B are illustration drawings showing a processing of basepoint recognition unit relating to the embodiment.

FIG. 8 is a flowchart showing a flow of a distance information obtainingprocessing to a next control point relating to the embodiment.

FIG. 9 is a flowchart showing a flow of a running situation monitoringprocessing to a next control point relating to the embodiment.

FIG. 10 is a drawing showing a method of determining a vertical linelength relating to the embodiment.

FIGS. 11A, 11B, 11C, and 11D are drawings respectively showing assumedrunning areas relating to the embodiment.

FIG. 12 is a flowchart showing a common processing of a control unitneeded for a control relating to the embodiment.

FIG. 13 is a control block diagram showing a control method associatedwith a control target relating to the embodiment.

FIG. 14 is an illustration drawing showing the Road Structure Ordinanceand a calculated lateral acceleration relating to the embodiment.

FIGS. 15A, 15B, 15C, 15D, and 15E are illustration drawings respectivelyshowing scenes to continuously execute a control to a continuous stopline control (rear video camera) relating to the embodiment.

FIGS. 16A, 16B, 16C, and 16D are illustration drawings respectivelyshowing scenes to continuously execute a control to a continuous stopline control (front video camera) relating to the embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

As shown in FIG. 1, a vehicle (not shown) runs along a route 101 c froma start point 101 a (mainly, a vehicle current position) to adestination 101 b. On the route 101 c are set at least one base point101 d and one control point 101 e, respectively.

The control points 101 e are points where a vehicle control is executedwhen the vehicle reaches there. In FIG. 1 three control points 101 e areshown with “” marks, respectively. When the vehicle reaches the controlpoints 101 e, respective vehicle controls of “right turn,” “left turn,”and “deceleration” are operated.

The base points 101 d are points where positioning is executed when thevehicle reaches there. The positioning is to acquire a vehicle currentposition at each base point 101 d by a highly accurate method that isneither an autonomous navigation nor a hybrid navigation, and to set theacquired highly accurate current position as a vehicle current position.A detail of the highly accurate method will be described later as a basepoint recognition.

For example, in FIG. 1 the two base points 101 d are shown with “O”marks, respectively, and when the vehicle reaches each base point 101 d,the positioning of the vehicle is executed. In addition, a position ofthe second base point 101 d from the start point 101 a is in common withthat of the first control point 101 e. Thus because a executed operationis independent between each base point 101 d and each control point 101e, both positions thereof may match.

In addition, a ground object of each base point 101 d is an object thatbecomes a recognition clue of the base point 101 d existing at the basepoint 101 d. For example, the ground object of the first base point 101d is a “landmark,” and that of the second base point 101 d is a “radiobeacon 101 f.” Furthermore, the ground object may also be adapted to berecognized from image data where a road is photographed by a videocamera; for example, a rhombus mark of a white line depicted in front ofa pedestrian crossing is one example of ground objects.

Then after the vehicle is positioned at the base point 101 d, thevehicle continues to acquire its current positions according to theautonomous navigation of accumulating differences of the currentpositions from the base point 101 d. Accordingly, the shorter a runningdistance from the base point 101 d is, the higher the accuracy of thevehicle current position becomes; thus the smaller the error of thecurrent position becomes. On the other hand, if a running distance fromthe base point 101 d becomes longer, the error of the vehicle currentposition becomes larger because the error is accumulated.

FIG. 2A is a graph showing a correlation between a running distance 102a and an cumulative error 102 b. The longer the running distance 102 ain a horizontal axis becomes, the larger the cumulative error 102 b in avertical axis becomes. In addition, the cumulative error 102 b is equalto an equation of: cumulative error 102 b=running distance 102a×accuracy+residual error (ε). Values of ε (for example, ε₀, ε₁)represent the residual error and are set as, for example, less than 2 m,depending on a positioning method and a position accuracy. If once thepositioning is executed, the cumulative error 102 b is cleared (0 m) ormodified into a value of a smaller residual error.

FIG. 2B is a table showing a correlation between the running distance102 a, the cumulative error 102 b, and a content of a vehicle controlaccording to the error 102 b. For example, when the running distance 102a is “100 m,” the cumulative error 102 b is “1+ε,” and as controlapplication examples, “speed limit running,” “deceleration at curve,”and “stop at stop line” can be executed.

In addition, as the item of the vehicle control, because needed positionaccuracy is comparatively rough in the “speed limit running” and the“deceleration at curve,” they can be executed until the cumulative error102 b becomes “10+ε.” On the other hand, because a high positionaccuracy is needed in the “stop at stop line,” it can be executed untilthe cumulative error 102 b becomes “2+ε.” Thus depending on the value ofthe cumulative error 102 b corresponding to the running distance 102 a,it is possible to select a vehicle control executable after the runningof a predetermined distance. Thus based on the calculation error of thevehicle current position, it is possible to execute the vehicle controlin line with a need.

Thus because the cumulative error 102 b becomes larger depending on therunning distance 102 a, an upper limit of the distance 102 a is definedwith respect to a vehicle control, where an accurate position control isneeded, such as a stop processing at a stop line; In the runningdistance 102 a not less than the upper limit, the vehicle control isstopped. Furthermore, when a plurality of vehicle controls aredesignated, a vehicle control to be activated is selected according tothe running distance 102 a.

The control points and the base points thus described are given inadvance as additional information to map data. In particular, in such acase of a route being fixed, a proper base point and control point and acontrol item are defined and reflected in map data, considering thecumulative error 102 b in order to be able to achieve the target.

A table 1 below shows a state change of a state change drawing of FIG. 3in a table format.

TABLE 1 State Input Next State Output Comment Autonomous Base PointAutonomous Positioning Continuation of Navigation 1 RecognitionNavigation 1 Autonomous Navigation 1 Control Point Autonomous ControlContinuation of Navigation 1 Execution Autonomous Navigation 1 ThresholdAutonomous State Change Running Distance 1 Navigation 2 Distance LimitOut of Route Without Control State Change Vehicle Instable WithoutControl State Change VDC Activation Timing and the like Autonomous BasePoint Autonomous State Change To Autonomous Navigation 2 RecognitionNavigation 1 Navigation 1 Control Point Autonomous Control Continuationof Navigation 2 Execution Autonomous Navigation 2 Threshold Hybrid StateChange Running Distance 2 Navigation Distance Limit Out of Route WithoutControl State Change Vehicle Instable Without Control State Change VDCActivation Timing and the like Hybrid Base Point Autonomous State ChangeNavigation Recognition Navigation 1 Control Point Hybrid ControlContinuation of Navigation Execution Hybrid Navigation Out of RouteWithout Control State Change Difficult to Without Control State ChangeVDC Receive GPS Activation Radio Wave Timing and the like VehicleInstable Without Control State Change Without-Control Base PointAutonomous State Change Recognition Navigation 1

As shown in FIG. 3, control states are classified into an in-control 103e and a without-control 103 f. States of the in-control 103 e areclassified into an autonomous navigation 103 d and a hybrid navigation103 c. States of the autonomous navigation 103 d are classified into anautonomous navigation “1” 103 a and an autonomous navigation “2” 103 b.

An item of an executable vehicle control is associated with each stateof the in-control 103 e. For example, in the autonomous navigation “1”103 a are executable the vehicle controls of the “stop at stop line” andthe “speed limit change.” A trigger for changing each state of thein-control 103 e is the running distance 102 a from a base point.

Firstly, if a base point is recognized, the control state is startedfrom the autonomous navigation “1” 103 a. Because in this state therunning distance 102 a is still short and the cumulative error 102 b isalso small, it is possible to execute various kinds of vehicle controlssuch as the “stop at stop line” and the “speed limit change.” If thebase point vehicle is not recognized, the running distance 102 a furtherincreases and reaches a predetermined threshold distance “1” 103 g, thecontrol state is changed to the autonomous navigation “2” 103 b.

In the autonomous navigation “2” 103 b, because the running distance 102a has already increased, such the “stop at stop line” that needs ahigher position accuracy is not executed, but a vehicle control such asthe “speed limit change” that does not need the higher position accuracyis executed.

If the running distance 102 a further increases and reaches apredetermined threshold distance “2” 103 h, it is determined that thevehicle has reached the running distance 102 a to which the autonomousnavigation 103 d is not applicable, and the state is changed to theconventional hybrid navigation 103 c. In the conventional hybridnavigation 103 c is executed a vehicle control such as the “speed limitchange” that does not need the higher position accuracy. In thein-control 103 e, a new base point recognition is made a trigger, thecontrol state is changed to the first autonomous navigation “1” 103 a.

Moreover, in a state of the vehicle being about to spin, a vehiclestabilizing apparatus operates and attempts to avoid the vehicle fromspinning. In the vehicle unstable state where the vehicle stabilizingapparatus works, the control state is changed to the without-control 103f, based on a control signal from the apparatus. On the other hand, alsowhen the vehicle current position is out of a route guided by anavigation system 330 (see FIG. 4) and thereby the vehicle runs out ofthe route, the control state is changed to the without-control 103 f. Inaddition, after the change to the without-control 103 f, a base pointrecognition is made a trigger and the vehicle control of the autonomousnavigation 103 d is restarted.

Furthermore, in the case of the hybrid navigation 103 c, a GPS radiowave is received and a vehicle current position is specified.Consequently, when a number (number of satellites) and radio waveintensity of received GPS radio waves are insufficient, it is difficultto specify the vehicle current position; therefore, the state is changedto the without-control 103 f. On the other hand, in the case of theautonomous navigation 103 d, the GPS radio wave is not used; therefore,the control state need not be changed. By dynamically changing thenavigations for specifying a vehicle current position according to thestate changes thus described, it is possible to broaden control ranges(time, item) of the vehicle control, based on the calculation error ofthe current position, and to provide a driver with a convenience.

For example, in a system where the hybrid navigation 103 c isindependently used, the control state comes into the without-control 103f when it is difficult to receive a GPS radio wave; therefore, thecontinuation of the vehicle control cannot be kept. On the other hand,as shown in FIG. 3, in a system where the autonomous navigation 103 d isused in combination with the hybrid navigation 103 c, the control statedoes not come into the without-control 103 f in the autonomousnavigation 103 d even when it is difficult to receive a GPS radio wave;therefore, the continuation of the vehicle control can be kept.

In addition, in the state change of the vehicle control a user can checkits current state according to the following method in addition to amethod of a vehicle control system VCS clearly indicating the currentstate in its display. The user intentionally turns off the GPS and makesa state in which a GPS signal does not come. If the current state is thehybrid navigation 103 c, the vehicle control is canceled due to thereception difficulty of a GPS radio wave. On the other hand, if thecurrent state is the autonomous navigation 103 d, the vehicle control iscontinuously executed, and the operations of the base point recognitionand the vehicle control are repeated.

As shown in FIG. 4, the vehicle control system VCS comprises a map data301, a route setting unit 302, a map point data 303, a GPS antenna 321,a driver's own vehicle speed detection unit 306, a direction detectionunit 307, a front recognition video camera 305 a, a rear recognitionvideo camera 305 b, a VICS (Vehicle Information and CommunicationSystem)® receiver 305 c, a hybrid navigation unit 322, an autonomousnavigation unit 323, a base point recognition unit 324, a control pointinformation obtaining unit 309, a running situation monitoring unit 310,an actuator control unit 311, and an actuator 312.

In addition, in the embodiment the navigation system 330 comprises themap data 301, the route setting unit 302, the map point data 303, theGPS antenna 321, and the hybrid navigation unit 322. Specifically, inthe navigation system 330 the route setting unit 302 sets a route, basedon information (such an address) for setting the route input by a usersuch as a driver. The navigation system 330 indicates in its display:the map data 301 with which the base point data 303 is associated; theroute set by the route setting unit 302; and a vehicle current positionacquired by the hybrid navigation 322. If the vehicle current positionis incessantly updated, the displayed range is scrolled in conjunctionwith the vehicle current position.

Furthermore, means for recognizing the vehicle current position uses thehybrid navigation unit 322, the autonomous navigation unit 323, and thebase point recognition unit 324. The base point recognition unit 324recognizes a base point based on information acquired by an environmentrecognition sensor (for example, any one of the front recognition videocamera 305 a, the rear recognition video camera 305 b, the VICS receiver305 c); and thereby recognizes the vehicle current position near thebase point (the detail will be described later).

The autonomous navigation unit 323 makes each position of base points asa reference, which the base point is recognized by the base pointrecognition unit 324; calculates a difference from the position of thebase points to the vehicle current position, based on output from thedriver's own speed detection unit 306 and the direction detection unit307; and thereby recognizes the vehicle current position.

The hybrid navigation unit 322 uses the GPS radio wave received by theGPS antenna 321 and the vehicle current position recognized by theautonomous navigation unit 323, and recognizes the vehicle currentposition.

A control unit 308 comprises the control point information obtainingunit 309, the running situation monitoring unit 310, and the actuatorcontrol unit 311. Here, although the actuator control unit 311 isincluded in the control unit 308, the unit 311 may be providedindependently of the control unit 308 or may be stored in another unit,to and from which data is interchangeable, such as any one of theactuator 312 and the base point recognition unit 324.

In addition, the vehicle control system VCS is configured to be acomputer comprising: at least a memory as a memory means used inexecuting a computation processing and a computation processing unit forexecuting the computation processing. In addition, the memory isconfigured with such a RAM (Random Access Memory). The computationprocessing is achieved by executing a program on the memory. Theembodiment includes, in addition to the computation processing unit, aprogram for making the processing unit execute the computationprocessing and a computer readable recording medium where the program isrecorded.

The route setting unit 302 refers to the map data 301 and the base pointdata 303, and sets a route (S11). The base point recognition unit basepoint recognition unit 324 executes the base point recognition (S12).

The control point information obtaining unit 309 obtains distanceinformation to a next control point (S13). As shown in FIG. 5, therunning situation monitoring unit 310 executes a running distancemeasurement by an autonomous navigation (S14). The actuator control unit311 executes the vehicle control at the control point (S15). Here willbe described each of the processings in detail.

The route setting (S11) will be described. The route setting unit 302 isan input unit for executing the route setting, and a route is fixed by adriver's operation (input of a destination, and a route selection from aplurality of route candidates). Next, the route setting unit 302searches and determines the information of a base point and a controlpoint existing in the fixed route from the map data 301.

As shown in FIG. 6A, the base point data 303 is represented bytwo-dimensional coordinates, and there exist a plurality of base points101 d (the alphanumeric code 101 d is omitted for simplification in FIG.6A and hereinafter will be also omitted in FIG. 6B and other drawings,and the description). Furthermore, with respect to each base point,there exists a control point 101 e (the alphanumeric code 101 e isomitted for simplification in FIG. 6A, and hereinafter will be alsoomitted in FIG. 6B and other drawings, and the description)corresponding to the base point. That is, the information of a basepoint is associated with that of a control point existing in a zonebetween base points.

FIG. 6B is a drawing showing a structure example of the base point data303. As control point information associated with the base point of thebase point data base point data base point data 303, the followings arestored: the position coordinates and control items of the control point;a way (actual distance of a vehicle running between two points, notalways the shortest distance) to the control point; the coordinates oftwo points on an assumed running route; and the width of an assumedrunning area. The way to the control point is used for an autonomousnavigation. A type of a ground object at a recognized base point is usedfor an application where the cumulative error 102 b is cleared or anassumed error is set as a residual error. Furthermore, at that time, itis also available to consider an error (for example, 1 to 2 m) indetermining a vehicle current position from a base point position, andto add the error to the residual error. In this connection, the errorsare various from a few centimeters to a few meters according to thespecifications of instruments similarly to the GPS.

In addition, when a route is fixed, the base point data 303 may beconstructed independently from the map data 301. Furthermore, in thedata structure example are omitted an index for high speed search, thenumber of data, and end determination data because they are not directlyrelated to the data structure.

Next will be described the base point recognition (S12).

The base point recognition unit 324 recognizes a road sign board abovethe ground, a road sign painted on the road, and the like that arerespectively recognized as base points by an environment recognitionsensor not shown. As the environment recognition sensor, a video camera,a radar, and their combination are used. Furthermore, it is alsoavailable to use a communication between vehicles on a road and toreceive a beacon position. The environment recognition sensor may be anytype of detecting the front or rear of a vehicle in order to recognizethe base point.

The outputs of the environment recognition sensor are, for example, theground object type of a recognized base point, a distance to the basepoint, a direction toward the base point, and a detected delay time.From the information output by the environment recognition sensor, thebase point recognition unit 324 makes the position of a known base pointa reference and accurately determines the vehicle current position.

As shown in FIG. 7A, objects at a base point are a stop line,information of a pedestrian crossing, a road sign such as a trafficclassification, a road sign board, and a beacon position, wherein theobjects are the ground object type. As shown in FIG. 7B, a vehicle Vcomprises, for example, at least one of the front recognition videocamera 305 a, the rear recognition video camera 305 b, and the VICSreceiver 305 c as an environment recognition sensor at a base point thatis an input in the base point recognition unit 324.

Next will be described the distance information obtaining (S13) to anext control point.

The control point information obtaining unit 309 obtains the currentposition of the vehicle V from the hybrid navigation unit 322, based onthe information of the base point recognition unit 324; and obtains thedistance information to the next control point, based on the informationof the base point data 303. The hybrid navigation unit 322 is based on aconventional technology and determines the current position of thevehicle V through the navigation 103 c that uses the GPS and theautonomous navigation. In addition, the navigation unit 322 is assumedto acquire the information of the autonomous navigation 103 d from theautonomous navigation unit 323, and to determine the current position ofthe vehicle V according to the hybrid navigation 103 c.

As shown in FIG. 8, firstly, the control point information obtainingunit 309 accepts the input of the base point recognition unit 324(S201), and obtains the ground object at the base point. Next, thecontrol point information obtaining unit 309 makes the current positionof the vehicle V and the ground object at the base point to be searchkeys, the current position and the ground object are obtained from thehybrid navigation unit 322, and searches the base point data 303obtained by the route setting unit 302. Then, out of many pieces of thebase point data 303, the control point information obtaining unit 309specifies a base point input this time (S202). Moreover, the controlpoint information obtaining unit 309 acquires control point informationassociated with the base point and sets the residual error (S203). Inaddition, “Return” in the flowchart of FIG. 8 means that the processingreturns to the main processing of FIG. 5 from the processing of the S13thereof. Then according to the main processing of FIG. 5 describedabove, the S14 next to the processing of the S13 is called.

Next will be described the running distance measurement (S14) accordingto the autonomous navigation 103 d.

The running situation monitoring unit 310 determines a running distanceand a direction from the base point, based on information output by thedriver's own vehicle speed detection unit 306 and the directiondetection unit 307. Specifically, the running situation monitoring unit310 determines the driver's own vehicle speed and direction according toa time, integrates their micro vectors, calculates a vehicle movementposition, and determines a vehicle current position and a way to thecurrent position.

The driver's own vehicle speed detection unit 306 may count a wheelspeed pulse and detect the own vehicle speed; and also, may use anacceleration sensor, integrates the acceleration, and thereby determinethe speed. Furthermore, an anti-braking control, a traction control, anda stability control are used for a vehicle stability; the detection unit306 may also use the result of a driver's own vehicle speed determinedfrom sensors used for the above controls, and the result of the ownvehicle speed determined from a vehicle control computation.

The direction detection unit 307 detects the advancing direction of thedriver's own vehicle. As the direction detection unit directiondetection unit 307, a gyro sensor, a geomagnetic sensor, a steeringangle sensor, and a yaw rate sensor can be used.

As shown in FIG. 9, firstly, the autonomous navigation unit 323determines the vehicle current position according to the autonomousnavigation 103 d (S301). Specifically, the autonomous navigation unit323 determines a unit-time distance vector from the vehicle speed andthe direction from the base point, and determines the vehicle currentposition (equation 1) that is a cumulative-distance vector from the basepoint:

current position vector=base point position vector+residual errorvector+Σdriver's own vehicle speed x direction vector×ΔT,  Eq. 1

where ΔT is a unit time.

Here, the residual error vector is set by multiplying the residual errorwith the direction vector at the base point position. Moreover, thedriver's own vehicle speed is integrated with respect to the time andthe way (equation 2) is determined:

way=residual error+Σdriver's own vehicle speed×ΔT  Eq. 2

Next, the autonomous navigation unit 323 determines whether or not adetermination condition of “the vehicle current position is within arange of an assumed running area” is satisfied (S302); if satisfied (Yesin the S302), the processing is changed to an S303; and if not satisfied(No in the S302), the processing is changed to a state “control cancel(without control).” The purpose of the determination in the S302 is tocheck that the vehicle advances toward the destination. Thedetermination is achieved, for example, by a calculation that thevehicle current position is not within the range of the assumed runningarea, when the length of a vertical line from the current position tothe assumed running route is determined and the length is out of (largerthan) its threshold (width of the assumed running area).

As shown in FIG. 10, it is possible to calculate and determine thevertical line from the coordinates of a line segment of the assumedrunning route and those of the vehicle current position. An example isshown where the Hero's formula is used by focusing on the triangle areaformed by the line segment of the assumed running route and the vehiclecurrent position.

As shown in FIGS. 11A, 11B, 11C, and 11D, in some cases there are aplurality of assumed running areas according to the road shapes of theassumed running route such as (a) a straight line, (b) an intersection,(c) a curve, and (d) a T junction. In these cases a line segment(assumed running route) having a nearest start point and end point fromthe vehicle current position is selected, and thereby the length of thevertical line and the width of the assumed running area are determined.

Then the autonomous navigation unit 323 determines whether or not adetermination condition of “the vehicle current position reaches thecontrol point” is satisfied (S303); if satisfied (Yes in the S303), theprocessing returns to the S15; and if not satisfied (No in the S303),the processing is changed to the S301.

As the determination method in the S303, the data of a running distanceand that of a way to the control point may be compared, and thecoordinates of the vehicle current position and those of the controlpoint may also be compared. It is desirable to use the data of the wayin which the error of the direction detection is not entered in casesof: the data of the way being collected by practically driving a vehiclein advance; and the accuracy of the data of the way being higher,wherein the data of the way is determined from the calculation of arunning route on a map.

Next will be described the vehicle control at the control point.

The control unit 308 obtains distance information to a next base point,monitors a running situation, and executes the vehicle control, based onthe information of the route setting unit 302, the hybrid navigationunit 322, the base point recognition unit 324, the driver's own vehiclespeed detection unit 306, and the direction detection unit 307.

The actuator control unit 311 executes controls such as a stop controlat a stop line and a speed limit change, and drives the actuator 312.The actuator control unit 311 drives the actuator 312 according to aninstruction from the control unit 308. As the actuator 312, thefollowings can be cited an engine 312 a, a brake 312 b, an AT (AutomaticTransmission) 312 c, and various alarm devices 312 d.

As shown in FIG. 12, firstly, a distance to the control point isdetermined (S401). It is possible to determine the distance from adifference between the vehicle current position calculated by theautonomous navigation unit 323 through the autonomous navigation 103 dand the control point obtained by the control point informationobtaining unit 309.

The actuator control unit 311 determines an arrival time (S402). Thearrival time is a distance and a driver's own vehicle speed to a targetobject set at the control point. The actuator control unit 311 executesa target control according to the distance and the arrival time to thetarget object.

TABLE 2 Number Control Target Control Method (1) Stop at Stop LineFirstly, make the vehicle speed relative to the stop line “zero,” andexecute the control so as to make the arrival time (distance anddriver's own vehicle speed) to the stop line constant. Secondly, if theown vehicle speed becomes slow (for example, a few kilometers/h, changethe control method, control the brake actuator through the open controlwhere the reaction time and stop distance of the actuator areconsidered, and thereby stop the vehicle at the stop line (2) SpeedLimit Change When the vehicle reaches the control point, adjust theupper speed limit with a new speed limit. (3) Deceleration before Give atarget vehicle speed to keep a Curve lateral acceleration, depending onthe curvature radius of a curve. (4) Branch Instruction If the targetarrival time (distance and driver's own vehicle speed) to theintersection is reached, issue an instruction to the man-machineinterface. The branch alarm may be output, depending on the distance tothe start of the branch road, and also on the arrival time at the road.The guidance for prompting any one of a left turn and a right turn canbe achieved by the method similar to the branch alarm. (5) Corner VideoActivate the corner video camera Camera Control automatically at such aT junction and an intersection, display such a vehicle from a side, andthereby call attention.

Table 2 shows the control target and the control method executed by theactuator control unit 311.

As shown in FIG. 13, the actuator control unit 311 comprises a headwaydistance control unit 311 a, a stop line control unit 311 b, acurve-entry-control unit 311 c.

Such a control method for making the arrival time constant as thecontrol method (1) in Table 2 is assumed to be used together with an ACC(Adaptive Cruise Control System). Specifically, in the ACC, by using acontrol method for making a speed relative to a preceding vehicle “zero”in following the preceding vehicle, and making a set arrival time(headway distance and driver's own vehicle speed) constant, it ispossible to achieve the control method for making the arrival timeconstant.

In the ACC the computation of a headway distance control is executed,based on a preceding-vehicle relative speed and the arrival time, andthereby the target speed of the ACC is determined. The actuator controlunit 311 selects a smaller one out of the target speed and an ACC setspeed set by a driver (“select low”), and sends the smaller one to theactuator 312. The actuator 312 controls the engine 312 a, the AT 312 b,and the brake 312 c so that the vehicle comes into a constant speed. Inaddition to the headway distance control unit 311 a, as shown in FIG.13, the stop line control unit 311 b is added. Then selecting three ofthe target speed according to the stop line, the ACC set speed, and theACC target speed, the ACC may give them to the actuator 312.

The “Speed Limit Change” of the control method (2) in Table 2corresponds to an ACC set target speed change of a conventionaltechnology, and it is possible to add the input of the speed limit inFIG. 13. The speed change after the target speed change is achievedsmoothly and without giving uncomfortable feeling to a driver.

Next will be described the control method (3) of “Deceleration beforeCurve” in Table 2. With respect to a lateral acceleration (lateral G) ata curve, the design speed and curvature radius of the curve are definedin the article 15 (curvature radius) of the Road Structure Ordinance.

As shown in FIG. 14, the lateral G is limited to about 2.5G. A targetspeed is controlled so that the lateral G is within a range of eachlateral acceleration constant. With respect to a deceleration method, arelative speed difference is determined between a current vehicle speedand a vehicle speed at a curve entry position, and then the ACC controlmay be used. Specifically, in FIG. 13 the deceleration method can beachieved by adding the curve entry control unit 311 c. In a scene on theway of the curve, it is available to add a vehicle speed at a curve,where the lateral G is considered, to the option of the “select low” ofthe vehicle speed control.

With respect to the control timing of the corner video camera in thecontrol method (5) of Table 2, the control may be started when thearrival time becomes equal to a control start time (=operation time ofcorner video camera+time delay).

Thus mainly referring to FIG. 5, the details of the route setting (S11)to the vehicle control in the control point (S15) have been described.

In executing the autonomous navigation 103 d, the learning function ofthe autonomous navigation 103 d may be used. Conventionally, in acar-navi (car navigation) a vehicle speed is determined mainly bymultiplying a vehicle speed pulse with a coefficient equivalent to thewheel radius. The coefficient is adapted to be always learned, forexample, by comparing vehicle direction change operations of a leftturn, a right turn, and a curve with reference positions on the map.Accordingly, in the autonomous navigation 103 d, because the learning ofthe coefficient is always executed, it is possible to reduce an error,for example, less than 1%, after an initial position is once adjusted.Accordingly, by using the autonomous navigation 103 d, it is possible toreduce a variation when a vehicle runs a same course a plurality oftimes.

Furthermore, in the autonomous navigation 103 d a complementary functionof using a sensor may be used. In a case of a tire idly rotating,depending on an environment condition, it is possible to correct thevehicle speed to a proper vehicle speed by referring to other wheelspeeds, an acceleration sensor, and an absolute vehicle speed sensor.

Here will be described using a function of determining the vehiclecurrent position, and a correction function of the current position bythe map matching of the car-navi at the same time. When the vehiclecurrent position after the map matching processing is used for thevehicle control, an error of the map and that of the map matching resultare reflected in the current position, and the vehicle is not alwaysarranged on the road continuously. Thus forcibly executing the mapmatching causes the accuracy of the vehicle current position to worsenon the contrary, and inadequately acts on the vehicle control.Therefore, conventionally, when a route is not certain, the vehiclecontrol is adapted to be cancelled soon.

Furthermore, the processings S12 to S15 may be continuously (repeatedly)executed for one route setting (S11). Here will be described arepeatedly executed example.

By simulating a route, it is possible to check that a plurality of basepoints and control points exist in the route in advance (beforerunning). For example, as shown in FIG. 6A, if base points and controlpoints are arranged so that a next base point “2” is recognized before acontrol point “1” is reached after the recognition of a base point “1,”a control flow associated with the base point recognition iscontinuously executed. In continuously executing the processings S12 toS15, the route setting to the destination may be executed, and then, thebase points and the control points may be selected.

Particularly when a route is fixed, a lacking base point and controlpoint may be checked and reflected in the map data 301 in addition to abase point and a control point that are already registered. Byrepeatedly executing an actual running, it is possible to furtherachieve an enhancement and to execute a stable running. When there exista plurality of vehicle controls (for example, “stop at stop line” and“corner video camera control”), it is possible to execute both, and alsoto choose and execute one of the both.

Furthermore, although the scene of recognizing a plurality of basepoints before arrival at the control point after the recognition of thebase point is considered, the data of a base point lastly recognized mayalso be adopted.

Each stop line in FIGS. 15A, 15B, 15C, 15D, and 15E is an example of abase point. The rear video camera 305 b is mounted on the vehicle V. Inaddition, each two-dimensional graph on the right side shows thecoordinate position of the vehicle V as a black circle or an arrow mark,and shows the coordinate position of a stop line as a white circle.

In the ‘stop line “1” detection’ of FIG. 15A, the stop line “1” isdetected by the rear video camera 305 b, and then stop controlinformation is obtained as the position, distance, and controlinformation of the next stop line “2.” In the “autonomous navigation 103d” of FIG. 15B, then the running of the vehicle V is started and itsposition is obtained according to the autonomous navigation 103 d. Inthe “deceleration control” of FIG. 15C, when the vehicle V reaches nearthe stop line “2,” the deceleration of the vehicle V is started. In the“kept stopped” of FIG. 15D, the stop control of the vehicle V isexecuted at the position of the stop line “2.”

In the ‘stop line “2” detection’ of FIG. 15E, the running of the vehicleV is started, the base point of the stop line “2” is recognized and stopcontrol information is obtained as the position, distance, and controlinformation of the next stop line “3.” In this example of FIGS. 15A-15Ethere exist a base point and a control point at a same position, andtherefore, it is not possible to recognize the stop line “2” of the nextbase point before the vehicle V stops at the stop line “2.” However, itis possible to recognize the stop line “2” with the rear video camera305 b from the stop state of the vehicle V at the stop line “2” justafter the running of the vehicle V is started. Accordingly, even whenthe position of a base point and that of a control point are same, it ispossible to execute a series of continual processings.

In FIGS. 16A, 16B, 16C, and 16D, each two-dimensional graph on the rightside shows the coordinate position of the vehicle V as a black circle oran arrow mark, and shows the coordinate position of a stop line as awhite circle. As shown in FIGS. 16A, 16B, 16C, and 16D, the front videocamera 305 a is mounted on the vehicle V. Although the example of therear video camera 305 b has been described in FIGS. 15A-15E, the vehicleV can be more accurately stopped at a stop line by using the front videocamera 305 a.

In the ‘stop line “1” detection’ of FIG. 16A, the stop line “1” isdetected by the front video camera 305 a, and then stop controlinformation is obtained as the position, distance, and controlinformation of the next stop line “2.” In the “autonomous navigation 103d” of FIG. 16B, the running of the vehicle V is started and its positionis obtained according to the autonomous navigation 103 d.

Next will be described the ‘deceleration control & stop line detection“2”’ of FIG. 16C. When the vehicle V arrives near the stop line “2,” thedeceleration of the vehicle V is started. When the stop line “2” isfound by the front video camera 305 a, a distance to the stop line “2”is detected, the stop line “2” is recognized as the base point, and theposition, distance, and control information of the stop line “3” isobtained.

Here, from a time when the stop line recognition is made possible by thefront video camera 305 a, it is requested to adopt the distance to thestop line “2” recognized by the front video camera 305 a instead of adistance to a stop line determined from the autonomous navigation 103 d.When the stop line “2” is found, the distance to the stop line “2” isobtained, the stop line “2” is recognized as the base point, and theposition, distance, and control information of the stop line “3” isobtained.

In the “kept stopped” of FIG. 16D, the stop control of the vehicle V atthe stop line “2” is executed, based on the position information of thestop line “2” by the front video camera 305 a.

1. A vehicle control system comprising: a route setting unit configuredto set a route from a start point to a destination; an informationobtaining unit configured to obtain from a memory position informationof at least one base point and at least one control point existing inthe route set by the route setting unit; a base point recognition unitconfigured to recognize that a current position of a vehicle reaches aposition of the base point obtained by the information obtaining unit; arunning situation monitoring unit configured to determine as apredetermined distance a running distance from the base point mostlately recognized by the base point recognition unit; and a control unitconfigured to execute an advanced control to the vehicle if thepredetermined distance determined by the running situation monitoringunit is shorter than any of a first threshold distance and a secondthreshold distance, when the current position of the vehicle reaches aposition of the control point obtained by the information obtainingunit, wherein the first threshold distance is shorter than the secondthreshold distance.
 2. The vehicle control system according to claim 1,wherein the information obtaining unit obtains a plurality of the basepoints and a plurality of the control points, and the control unitexecutes vehicle controls at the control points a plurality of times. 3.The vehicle control system according to claim 1, wherein the informationobtaining unit obtains the position information of the base point andthe control point from a navigation system mounted on the vehicle. 4.The vehicle control system according to claim 1, wherein when thepredetermined distance is shorter than the second threshold distance,the control unit detects a current position of the vehicle according toan autonomous navigation, and wherein when the predetermined distance isequal to or longer than the second threshold distance, the control unitdetects a current position of the vehicle according to a hybridnavigation.
 5. The vehicle control system according to claim 1, whereinthe base point recognition unit recognizes the vehicle arriving at aposition of a base point through a ground object photographed by a videocamera mounted on the vehicle.
 6. The vehicle control system accordingto claim 1, wherein the base point recognition unit recognizes thevehicle arriving at a position of a base point through a radio wavereceived from a beacon near the vehicle.
 7. The vehicle control systemaccording to claim 1, wherein the control unit controls at least one ofa stop at a stop line, a speed change, a deceleration before a curve, aturn signal, and a following of a preceding vehicle.
 8. A vehiclecontrol method through a computer in a vehicle control system includinga route setting unit, an information obtaining unit, a base pointrecognition unit, a running situation monitoring unit, and a controlunit, the vehicle control method comprising the steps of the routesetting unit setting a route from a start point to a destination; theinformation obtaining unit obtaining from a memory position informationof at least one base point and at least one control point existing inthe route set by the route setting unit; the base point recognition unitrecognizing that a current position of a vehicle reaches a position ofthe base point obtained by the information obtaining unit; the runningsituation monitoring unit determining as a predetermined distance arunning distance from the base point most lately recognized by the basepoint recognition unit; and the control unit executing an advancedcontrol to the vehicle if the predetermined distance determined by therunning situation monitoring unit is shorter than any of a firstthreshold distance and a second threshold distance, when the currentposition of the vehicle reaches a position of the control point obtainedby the information obtaining unit, wherein the first threshold distanceis shorter than the second threshold distance.
 9. A vehicle controlprogram for a vehicle control system including a route setting unit, aninformation obtaining unit, a base point recognition unit, a runningsituation monitoring unit, and a control unit, the vehicle controlprogram making a computer execute the steps of: the route setting unitsetting a route from a start point to a destination; the informationobtaining unit obtaining from a memory position information of at leastone base point and at least one control point existing in the route setby the route setting unit; the base point recognition unit recognizingthat a current position of a vehicle reaches a position of the basepoint obtained by the information obtaining unit; the running situationmonitoring unit determining as a predetermined distance a runningdistance from the base point most lately recognized by the base pointrecognition unit; and the control unit executing an advanced control tothe vehicle if the predetermined distance determined by the runningsituation monitoring unit is shorter than any of a first thresholddistance and a second threshold distance, when the current position ofthe vehicle reaches a position of the control point obtained by theinformation obtaining unit, wherein the first threshold distance isshorter than the second threshold distance.